Critical care nursing clinics of North America
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The purpose of this article is to propose optimal weaning of vasopressors in patients with septic shock. Topics discussed include pathophysiology of sepsis and septic shock, treatment guidelines for sepsis, autoregulation of blood flow, vasopressors used in septic shock, weaning recommendations, monitor alarms in the intensive care unit, and new directions in sepsis research.
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Crit Care Nurs Clin North Am · Sep 2014
ReviewThe physiologic role of erythrocytes in oxygen delivery and implications for blood storage.
Erythrocytes are not just oxygen delivery devices but play an active metabolic role in modulating microvascular blood flow. Hemoglobin and red blood cell morphology change as local oxygen levels fall, eliciting the release of adenosine triphosphate and nitric oxide to initiate local vasodilation. ⋯ This article reviews the functional anatomy and applied physiology of the erythrocyte and the microcirculation with an emphasis on how erythrocytes modulate microvascular function. The effects of cell storage on the metabolic functions of the erythrocyte are also briefly discussed.
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Functional components of the microcirculation provide oxygen and nutrients and remove waste products from the tissue beds of the body's organs. Shock states overwhelmingly stress functional capacity of the microcirculation, resulting in microcirculatory failure. ⋯ In nonseptic shock states, the microcirculation is better able to compensate for alterations in vascular resistance, cardiac output, and blood pressure. Therefore, global hemodynamic and oxygen delivery parameters are appropriate for assessing, monitoring, and guiding therapy in hypovolemic and cardiogenic shock but, alone, are inadequate for septic shock.
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Crit Care Nurs Clin North Am · Sep 2014
ReviewMonitoring tissue blood flow and oxygenation: a brief review of emerging techniques.
This article describes promising emerging technologies developed for measuring tissue-level oxygenation or perfusion, each with its own inherent limitations. The end user must understand what the instrument measures and how to interpret the readings. ⋯ Assessment of the metabolic state of the extracellular space with existing technology and proxy indicators of metabolic status are discussed. Also addressed are potential sources of variation for each technique, and the role that the clinician plays in the proper interpretation of the data.
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Crit Care Nurs Clin North Am · Sep 2014
ReviewExploring hemodynamics: a review of current and emerging noninvasive monitoring techniques.
The lack of randomized controlled trials suggesting improved outcomes with pulmonary artery catheter use and pressure-based hemodynamic monitoring has led to a decrease in pulmonary artery catheter use. However, an increasing amount of literature supporting stroke volume optimization (SVO) has caused a paradigm shift from pressure-based to flow-based techniques. This article discusses emerging flow-based techniques, supporting evidence, and considerations for use in critical care for methods such as Doppler, pulse contour, bioimpedance, bioreactance, and exhaled carbon dioxide. Regardless of the device chosen, the SVO algorithm approach should be considered, and volume challenges should be guided by dynamic assessments of fluid responsiveness.